ADU Floor Plans

ADU Floor Plans: 25 Layouts, Drawn to Scale

Studios to three bedrooms, 240 to 1,200 square feet, every one with room dimensions, door swings and what it costs to build. I drew all of them for this site, so nothing here is somebody else's plan.

Most ADU floor plans you find online are marketing for a company that wants to build them for you, which is fine until you notice that every plan happens to be the plan they already build. These are not that. I drew them as generic arrangements to show what actually fits at each size, including the versions that do not work as well, because knowing which layout you do not want is most of the value.

Use them to decide what you want before you pay a designer to draw it. That is the expensive mistake this page exists to prevent: hiring someone to produce a layout you reject at first sight, then paying again.

Every drawing carries its own dimensions, so you can hold it against your own lot. When you want the money side, each plan page has a cost table from the same engine that powers our estimator, and the cost by size pages go deeper on any one of them.

Browse every plan

Filter by size, bedrooms or build type. Every plan stays on the page, so nothing here is hidden behind a click.

Size
Bedrooms
Type

Showing all 25 plans

240 sq ft ADU floor plan, studio, 1 bath, layout A: dimensioned schematic showing room sizes and door placement

240 Sq Ft Garage Conversion Floor Plan: Studio, 1 Bath (Layout A)

A standard one-car garage, 12 by 20, converted to a studio.

Size
240 sq ft
Layout
Studio, 1 Bath
Build
$32,940–$54,900
240 sq ft ADU floor plan, studio, 1 bath, layout B: dimensioned schematic showing room sizes and door placement

240 Sq Ft Garage Conversion Floor Plan: Studio, 1 Bath (Layout B)

A narrow 10 by 24 garage, common on older lots.

Size
240 sq ft
Layout
Studio, 1 Bath
Build
$32,940–$54,900
400 sq ft ADU floor plan, studio, 1 bath, layout A: dimensioned schematic showing room sizes and door placement

400 Sq Ft ADU Floor Plan: Studio, 1 Bath (Layout A)

Square 20 by 20 footprint with the wet rooms stacked on one wall.

Size
400 sq ft
Layout
Studio, 1 Bath
Build
$90,000–$150,000
400 sq ft ADU floor plan, studio, 1 bath, layout B: dimensioned schematic showing room sizes and door placement

400 Sq Ft ADU Floor Plan: Studio, 1 Bath (Layout B)

Long 16 by 25 footprint for a narrow side yard.

Size
400 sq ft
Layout
Studio, 1 Bath
Build
$90,000–$150,000
440 sq ft ADU floor plan, 1 bed, 1 bath, layout A: dimensioned schematic showing room sizes and door placement

440 Sq Ft Garage Conversion Floor Plan: 1 Bed, 1 Bath (Layout A)

A two-car garage, 20 by 22, converted to a one bedroom.

Size
440 sq ft
Layout
1 Bed, 1 Bath
Build
$60,390–$100,650
440 sq ft ADU floor plan, 1 bed, 1 bath, layout B: dimensioned schematic showing room sizes and door placement

440 Sq Ft Garage Conversion Floor Plan: 1 Bed, 1 Bath (Layout B)

A wider 22 by 20 garage with the living space across the front.

Size
440 sq ft
Layout
1 Bed, 1 Bath
Build
$60,390–$100,650
500 sq ft ADU floor plan, studio, 1 bath, layout C: dimensioned schematic showing room sizes and door placement

500 Sq Ft ADU Floor Plan: Studio, 1 Bath (Layout C)

The largest studio a junior ADU can legally be, at exactly 500 sq ft.

Size
500 sq ft
Layout
Studio, 1 Bath
Build
$112,500–$187,500
500 sq ft ADU floor plan, 1 bed, 1 bath, layout A: dimensioned schematic showing room sizes and door placement

500 Sq Ft ADU Floor Plan: 1 Bed, 1 Bath (Layout A)

Bedroom and bath at the back, living and kitchen across the front.

Size
500 sq ft
Layout
1 Bed, 1 Bath
Build
$112,500–$187,500
500 sq ft ADU floor plan, 1 bed, 1 bath, layout B: dimensioned schematic showing room sizes and door placement

500 Sq Ft ADU Floor Plan: 1 Bed, 1 Bath (Layout B)

Wide 25 by 20 footprint with a full-width living room.

Size
500 sq ft
Layout
1 Bed, 1 Bath
Build
$112,500–$187,500
600 sq ft ADU floor plan, 1 bed, 1 bath, layout A: dimensioned schematic showing room sizes and door placement

600 Sq Ft ADU Floor Plan: 1 Bed, 1 Bath (Layout A)

A generous one bedroom with a real closet and a proper kitchen.

Size
600 sq ft
Layout
1 Bed, 1 Bath
Build
$135,000–$225,000
600 sq ft ADU floor plan, 1 bed, 1 bath, layout B: dimensioned schematic showing room sizes and door placement

600 Sq Ft ADU Floor Plan: 1 Bed, 1 Bath (Layout B)

Deep 20 by 30 plan with a galley kitchen separating the zones.

Size
600 sq ft
Layout
1 Bed, 1 Bath
Build
$135,000–$225,000
600 sq ft ADU floor plan, 2 bed, 1 bath, layout C: dimensioned schematic showing room sizes and door placement

600 Sq Ft ADU Floor Plan: 2 Bed, 1 Bath (Layout C)

Two small bedrooms in 600 sq ft, with the service core in the middle.

Size
600 sq ft
Layout
2 Bed, 1 Bath
Build
$135,000–$225,000
750 sq ft ADU floor plan, 2 bed, 1 bath, layout A: dimensioned schematic showing room sizes and door placement

750 Sq Ft ADU Floor Plan: 2 Bed, 1 Bath (Layout A)

Two comfortable bedrooms at exactly the California fee threshold.

Size
750 sq ft
Layout
2 Bed, 1 Bath
Build
$168,750–$281,250
750 sq ft ADU floor plan, 2 bed, 1 bath, layout B: dimensioned schematic showing room sizes and door placement

750 Sq Ft ADU Floor Plan: 2 Bed, 1 Bath (Layout B)

Wide 30 by 25 plan with the bath between the two bedrooms.

Size
750 sq ft
Layout
2 Bed, 1 Bath
Build
$168,750–$281,250
800 sq ft ADU floor plan, 2 bed, 1 bath, layout A: dimensioned schematic showing room sizes and door placement

800 Sq Ft ADU Floor Plan: 2 Bed, 1 Bath (Layout A)

The size California guarantees, laid out as a roomy two bedroom.

Size
800 sq ft
Layout
2 Bed, 1 Bath
Build
$180,000–$300,000
800 sq ft ADU floor plan, 2 bed, 1 bath, layout B: dimensioned schematic showing room sizes and door placement

800 Sq Ft ADU Floor Plan: 2 Bed, 1 Bath (Layout B)

Narrow 20 by 40 plan for a deep lot or a tight side setback.

Size
800 sq ft
Layout
2 Bed, 1 Bath
Build
$180,000–$300,000
800 sq ft ADU floor plan, 2 bed, 2 bath, layout A: dimensioned schematic showing room sizes and door placement

800 Sq Ft ADU Floor Plan: 2 Bed, 2 Bath (Layout A)

Two baths in 800 sq ft, with the second one off the hall.

Size
800 sq ft
Layout
2 Bed, 2 Bath
Build
$180,000–$300,000
800 sq ft ADU floor plan, 2 bed, 2 bath, layout B: dimensioned schematic showing room sizes and door placement

800 Sq Ft ADU Floor Plan: 2 Bed, 2 Bath (Layout B)

Deep plan with an en suite primary bedroom and a walk-in closet.

Size
800 sq ft
Layout
2 Bed, 2 Bath
Build
$180,000–$300,000
800 sq ft ADU floor plan, 2 bed, 2 bath, layout A, 2 levels: dimensioned schematic showing room sizes and door placement

800 Sq Ft Two-Story ADU Floor Plan: 2 Bed, 2 Bath (Layout A)

400 sq ft footprint over two levels, for a lot with no room to spread.

Size
800 sq ft
Layout
2 Bed, 2 Bath
Build
$180,000–$300,000
816 sq ft ADU floor plan, 2 bed, 2 bath, layout B, 2 levels: dimensioned schematic showing room sizes and door placement

816 Sq Ft Two-Story ADU Floor Plan: 2 Bed, 2 Bath (Layout B)

Wider 24 by 17 footprint with the stair pulled to the centre.

Size
816 sq ft
Layout
2 Bed, 2 Bath
Build
$183,600–$306,000
1000 sq ft ADU floor plan, 2 bed, 2 bath, layout A: dimensioned schematic showing room sizes and door placement

1,000 Sq Ft ADU Floor Plan: 2 Bed, 2 Bath (Layout A)

Deep plan with two en suite bedrooms and a 375 sq ft living end.

Size
1,000 sq ft
Layout
2 Bed, 2 Bath
Build
$225,000–$375,000
1000 sq ft ADU floor plan, 2 bed, 2 bath, layout B: dimensioned schematic showing room sizes and door placement

1,000 Sq Ft ADU Floor Plan: 2 Bed, 2 Bath (Layout B)

Wide 40 by 25 plan with bedrooms at opposite ends.

Size
1,000 sq ft
Layout
2 Bed, 2 Bath
Build
$225,000–$375,000
1000 sq ft ADU floor plan, 3 bed, 2 bath, layout C: dimensioned schematic showing room sizes and door placement

1,000 Sq Ft ADU Floor Plan: 3 Bed, 2 Bath (Layout C)

Three bedrooms squeezed into the largest state-protected size.

Size
1,000 sq ft
Layout
3 Bed, 2 Bath
Build
$225,000–$375,000
1200 sq ft ADU floor plan, 3 bed, 2 bath, layout A: dimensioned schematic showing room sizes and door placement

1,200 Sq Ft ADU Floor Plan: 3 Bed, 2 Bath (Layout A)

A full three bedroom house, with a 210 sq ft primary suite.

Size
1,200 sq ft
Layout
3 Bed, 2 Bath
Build
$270,000–$450,000
1200 sq ft ADU floor plan, 3 bed, 2 bath, layout B: dimensioned schematic showing room sizes and door placement

1,200 Sq Ft ADU Floor Plan: 3 Bed, 2 Bath (Layout B)

Wide 40 by 30 plan with a 208 sq ft open living end.

Size
1,200 sq ft
Layout
3 Bed, 2 Bath
Build
$270,000–$450,000

Generic concept layout, not a construction drawing. Any real build needs site-specific stamped plans.

Plans by size, bedrooms and type

Each page walks its layouts one at a time: what works, what to watch, and what it costs to build.

500 sq ft plansThe junior ADU ceiling, drawn as a studio and as two one bedrooms.View plans600 sq ft plansWhere a one bedroom stops feeling like a compromise.View plans800 sq ft plansThe most requested size, in one bath and two bath versions.View plans1,000 sq ft plansThe largest unit the state requires a city to allow.View plans1,200 sq ft plansA full three bedroom house, if your ordinance allows it.View plansStudio plansFrom a converted one-car garage up to the 500 sq ft JADU ceiling.View plans1 bedroom plansSix layouts from a converted two-car garage to a roomy 600 sq ft build.View plans2 bedroom plansNine layouts from a tight 600 sq ft up to a full 1,000.View plansGarage conversion plansOne-car and two-car garages, drawn at their real dimensions.View plans2 story plansAround 800 sq ft stacked on a footprint half that size.View plans

Frequently asked questions

Are these ADU floor plans free to use?

They are free to look at, think with and share, and that is what they are for. They are not construction documents and cannot be permitted or built from. Any real project needs site-specific plans stamped by a licensed designer or engineer for your lot, or a plan from a city pre-approved program. What these drawings save you is the earlier and more expensive mistake: paying a designer to draw a layout you would have rejected on sight.

What is the most common ADU floor plan size?

Around 600 to 800 square feet, which is where a one bedroom stops feeling tight and a two bedroom becomes possible. In California 800 square feet is also the size the state requires cities to permit, so it turns up in city plan catalogues more than any other. Below 500 you are drawing a studio, and above 1,000 you are usually asking your city for permission rather than exercising a right.

What is the difference between ADU floor plans and pre-approved ADU plans?

A floor plan shows the layout. A pre-approved plan is a complete permit-ready set that a city has already reviewed for code compliance, so your application skips most of plan check. Since January 1, 2025, Government Code section 65852.27 requires every California local agency to run a preapproval program and post the approved plans online. We cover which cities have real catalogues and which have an empty page on our pre-approved ADU plans guide.

How many bedrooms fit in an ADU?

One bedroom fits comfortably from about 500 square feet, two from about 700, and three from about 1,000 if you accept small secondary bedrooms. California requires cities to allow up to 1,000 square feet for an ADU with more than one bedroom, so a two bedroom design is what unlocks the largest guaranteed size. A junior ADU is capped at 500 square feet and is realistically a studio or a very compact one bedroom.

Can I build an ADU from a plan I found online?

Not directly, no. A permit needs a site-specific set showing your lot, your setbacks, your utility connections, your soil and your structural design, sealed by someone licensed to seal it. What a plan you found online is genuinely good for is deciding what you want before you pay for that set, and for having a specific conversation with a designer instead of an abstract one.